package org.bouncycastle.asn1.x509;

import java.io.IOException;
import java.util.Hashtable;
import java.util.Vector;

import org.bouncycastle.asn1.ASN1Encodable;
import org.bouncycastle.asn1.DEREncodable;
import org.bouncycastle.asn1.DERObjectIdentifier;
import org.bouncycastle.asn1.DEROctetString;

/**
 * Generator for X.509 extensions
 */
@SuppressWarnings({ "rawtypes", "unchecked" })
public class X509ExtensionsGenerator {
    private Hashtable extensions = new Hashtable();
    private Vector extOrdering = new Vector();

    /**
     * Reset the generator
     */
    public void reset() {
        extensions = new Hashtable();
        extOrdering = new Vector();
    }

    /**
     * Add an extension with the given oid and the passed in value to be
     * included in the OCTET STRING associated with the extension.
     * 
     * @param oid
     *            OID for the extension.
     * @param critical
     *            true if critical, false otherwise.
     * @param value
     *            the ASN.1 object to be included in the extension.
     */
    public void addExtension(DERObjectIdentifier oid, boolean critical,
            DEREncodable value) {
        try {
            this.addExtension(oid, critical,
                    value.getDERObject().getEncoded(ASN1Encodable.DER));
        } catch (IOException e) {
            throw new IllegalArgumentException("error encoding value: " + e);
        }
    }

    /**
     * Add an extension with the given oid and the passed in byte array to be
     * wrapped in the OCTET STRING associated with the extension.
     * 
     * @param oid
     *            OID for the extension.
     * @param critical
     *            true if critical, false otherwise.
     * @param value
     *            the byte array to be wrapped.
     */
    public void addExtension(DERObjectIdentifier oid, boolean critical,
            byte[] value) {
        if (extensions.containsKey(oid)) {
            throw new IllegalArgumentException("extension " + oid
                    + " already added");
        }

        extOrdering.addElement(oid);
        extensions.put(oid, new X509Extension(critical, new DEROctetString(
                value)));
    }

    /**
     * Return true if there are no extension present in this generator.
     * 
     * @return true if empty, false otherwise
     */
    public boolean isEmpty() {
        return extOrdering.isEmpty();
    }

    /**
     * Generate an X509Extensions object based on the current state of the
     * generator.
     * 
     * @return an X09Extensions object.
     */
    public X509Extensions generate() {
        return new X509Extensions(extOrdering, extensions);
    }
}
